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The Southeast Asian scincid lizard
Siaphos tridigitus Bourret, 1939
(Reptilia, Scincidae): a second specimen
Allen E. GREER
Herpetology Section, Australian Museum,
6 College Street, Sydney, NSW 2010 (Australia)
[email protected]
Patrick DAVID
Muséum national d’Histoire naturelle, Département Systématique et Évolution,
Reptiles et Amphibiens, USM 602 Taxonomie et Collections,
case postale 30, 57 rue Cuvier, F-75231 Paris cedex 05 (France)
[email protected]
Alexandre TEYNIÉ
Association “Société d’Histoire naturelle Alcide d’Orbigny”,
27 route de la Tour d’Auvergne, F-63970 Aydat (France)
[email protected]
Greer A. E., David P. & Teynié A. 2006. — The Southeast Asian scincid lizard Siaphos tridigitus
Bourret, 1939 (Reptilia, Scincidae): a second specimen. Zoosystema 28 (3) : 785-790.
KEY WORDS
Reptilia,
Lacertilia,
Scincidae,
Siaphos tridigitus,
Sphenomorphus,
Laos,
Vietnam,
morphology.
ABSTRACT
A scincid lizard recently collected in Boloven Highlands, South Laos, proved
to be the second known specimen of Siaphos tridigitus Bourret, 1939. This
species was previously known only from its holotype obtained at Bach Ma,
central Vietnam. The new specimen is described and depicted, and compared
with the holotype. Relationships of this species are discussed. It is tentatively
placed in the genus Sphenomorphus Fitzinger, 1843.
MOTS CLÉS
Reptilia,
Lacertilia,
Scincidae,
Siaphos tridigitus,
Sphenomorphus,
Laos,
Vietnam,
morphologie.
RÉSUMÉ
Deuxième spécimen connu du scinque d’Asie du Sud-Est Siaphos tridigitus Bourret,
1939 (Reptilia, Scincidae).
Un spécimen de scincidé récemment collecté dans les monts Boloven, au sud
du Laos, représente le deuxième spécimen connu de Siaphos tridigitus Bourret,
1939. Cette espèce n’était connue que par son holotype originaire de Bach Ma,
au centre du Vietnam. Le nouveau spécimen est décrit et illustré, et comparé avec
l’holotype. Les relations de cette espèce sont examinées. Elle est provisoirement
placée dans le genre Sphenomorphus Fitzinger, 1843.
ZOOSYSTEMA • 2006 • 28 (3) © Publications Scientifiques du Muséum national d’Histoire naturelle, Paris.
www.zoosystema.com
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Greer A. E. et al.
INTRODUCTION
Bourret (1939) described, as Siaphos tridigitum, a
small skink from “Bach Ma, Annam”, now Bach Ma,
Thua Thien-Hue Province, Vietnam. The description
was based on a single specimen (MNHN 1948.0060,
Paris) found dead on the road and presented to him
by Monsieur Poilane. The specimen was probably
not in a good state of preservation when found
to judge from the circumstances of its discovery
and certain aspects of shape in the original figure
(Bourret 1939: fig. 7), which when seen in the actual
specimen are clearly due to moderate desiccation
and perhaps a mild degree of putrefaction. The
unique specimen was unusual in several regards,
most notably in having only three digits on the
front foot. The species has not been seen again (see
for example, Nguyen & Ho 1996), and under the
IUCN “50 year rule” (if a species has not seen for
50 years, a presumption of extinction is warranted)
might have been thought extinct. However, a second
specimen has recently come to light in South Laos
(Teynié et al. 2004), which not only demonstrates
that the species is still extant but also provides a basis
for a more detailed description and an assessment
of possible relationships. The genus Siaphos Gray,
1839, an emendation of Saiphos Gray, 1831, being
masculine, the species should be known as Siaphos
tridigitus.
The second specimen (MNHN 2003.3367; sex
unknown) was obtained during a herpetological
survey of the herpetofauna of South Laos conducted
by members of the association “Société d’Histoire
naturelle Alcide d’Orbigny” (Clermont-Ferrand,
France). It was collected in Sepian, Boloven Highlands, Champasak Province, Laos, at about 12001250 m a.s.l. (Fig. 1). The animal was collected at
day, hidden inside a log lying on grass near a small
creek in an open forest.
ABBREVIATIONS
Morphological abbreviations
Measurements
HL
head length;
SVL
snout-vent length.
Scalation
C
chin scale;
F
frontal;
786
FN
FP
IL
IP
L
M
N
NU
P
PF
PM
PO
PSL
PSO
PT
R
SC
SL
SO
frontonasal;
frontoparietal;
infralabial;
interparietal;
loreal;
mental;
nasal;
nuchal;
parietal;
prefrontal;
postmental;
preocular;
postsupralabial;
presubocular;
pretemporal;
rostral;
supraciliary;
supralabial;
supraocular.
Abbreviations of collections
BMNH
MNHN
NHMB
RMNH
British Museum of Natural History (now
The Natural History Museum), London;
Muséum national d’Histoire naturelle, Paris;
Naturhistorisches Museum Basel;
Rijksmuseum van Natuurlijke Historie
(now National Museum of Natural History), Leiden.
SPECIMENS EXAMINED. — Sphenomorphus alfredi: BMNH
1946.8.19.40 (holotype). — Sphenomorphus butleri:
BMNH 1946.8.17.7-9 (syntypes). — Sphenomorphus
cophias: BMNH 1946.8.3.15 (holotype). — Sphenomorphus parvus: NHMB 4738 (holotype). — S. sananus:
RMNH 5508 (syntype).
RESULTS
DESCRIPTION OF THE SECOND SPECIMEN OF
SIAPHOS TRIDIGITUS (FIGS 2; 3)
Morphology
In general aspect, a small (SVL 36.5 mm), medium
brown skink with a thin darker brown dorsolateral
stripe and relatively short limbs, the anterior pair
of which are tridactyle and the posterior pair pentadactyle.
In detail, HL 6.35 mm; SVL 36.5 mm, 5.7
times length of head (= elongation index); front
limb 5 mm, 13.7% of snout-vent length and with
three digits; rear limb 8.5 mm, 23.6% of SVL and
with five digits; on pes, digit four slightly shorter
ZOOSYSTEMA • 2006 • 28 (3)
Siaphos tridigitus (Reptilia, Scincidae) from Southeast Asia
than digit three; dorsal scales on fourth digit of
pes, in two rows basally and in single row of three
scales distally; subdigital lamellae on fourth digit
of pes 7-8.
Scalation
Rostral a half circle in apical view; supranasals
absent; frontonasal wider than long; prefrontals
widely separated; supraoculars four, first two
contact frontal on each size; frontoparietals
present; interparietal present, larger than either
frontoparietal; parietal eyespot present; parietals
meet posterior to interparietal; wide nuchals two
on each side.
Nasal and first supralabial fused; nostril in dorsal central position in combined nasal and first
supralabial; loreal single; presuboculars two, upper much smaller than lower; preocular single;
supraciliaries seven, first contacts frontal, first
three contact first supraocular on each side, sixth
large and projecting slightly between third and
fourth supraoculars; pretemporals two; postsuboculars two; upper palpebrals in contact with
supraciliaries, last large and projecting medially;
lower eyelid moveable, scaly, its lowermost row
of scales becoming pigmented and extending
outside eyelid proper; primary temporal single;
secondary temporals two, upper overlaps lower;
tertiary temporal single; supralabials six (counting
supranasal fused to nasal as first); postsupralabials two; external ear opening absent, its position
indicated by scaly depression.
Mental a half oval in apical view; postmental
wider than long; infralabials five on each side, first
(only) contacts postmental; pairs of large chin scales
three, members of first pair in contact, members of
second pair separated by one scale and members of
third pair separated by three scales.
Body scales smooth, glossy; longitudinal scale
rows at midbody 18; paravertebral scale rows 50,
slightly larger than more lateral scales; inner preanals overlap outer; mid-ventral caudals in six pairs
basally and in single wide row distally.
Colour in preservative
Dorsum medium brown; a thin diffuse dark brown
dorsolateral stripe; lower sides brown spotted; sides
ZOOSYSTEMA • 2006 • 28 (3)
FIG. 1. — Distribution of Sphenomorphus tridigitus Bourret, 1939
in Southeast Asia.
FIG. 2. — The second specimen of Sphenomorphus tridigitus
Bourret, 1939 (MNHN 2003.3367).
of chin dark spotted; venter of neck and body
plain; venter of tail dark spotted basally, suddenly
becoming gray over regenerated portion.
Osteology
Presacral vertebrae 27; phalanges of manus/pes
0.3.4.4.0/2.3.4.4.3 (bold shows digits reduced from
the phalangeal configuration that is almost certainly
primitive for Squamates [Romer 1956], skinks and
Sphenomorphus: 2.3.4.5.3/2.3.4.5.4).
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Greer A. E. et al.
TABLE 1. — Small species of Sphenomorphus Fitzinger, 1843 from Southeast Asia that share four or more derived character states
with Siaphos tridigitus Bourret, 1939.
Character
S. alfredi
S. parvus
S. butleri
S. cophias
S. sananus
(Boulenger, (Boulenger,
(Boulenger,
(Boulenger,
(Kopstein,
1898)
1897)
1912)
1908)
1926)
Prefrontals separated
+
–
–
+
–
Anterior supraciliary contacts frontal
+
+
+
?
–
Nasal and first supranasal fused
–
–
–
–
–
Loreal single
+
–
–
–
–
Supralabials six
+
+
+
+
+
Ear opening absent
–
+
–
+
+
Infralabials contacting
+
+
+
–
+
postmental one
Manus phalanges
+
+
+
+
+
< 2.3.4.4.3
2.3.4.4.3
2.3.4.4.3
2.3.4.4.3
2.3.4.4.3
2.3.4.4.?
Pes phalanges
–
+
–
–
–
< 2.3.4.4.3
2.3.4.5.4
?.?.4.4.3
2.3.4.5.4
2.3.4.5.4
2.3.4.5.4
Distribution
North Borneo Sulawesi,
Larut Hills,
Gunung Tahan,
Sula Is.,
Indonesia Perak, Malaysia Pahang, Malaysia Indonesia
DISCUSSION
COMMENTS ON THE ORIGINAL DESCRIPTION
OF SIAPHOS TRIDIGITUS
The original description does not conform to the
actual specimen in two important regards. First, and
perhaps most importantly, there were said to be a
pair of symmetrical scales in place of the frontonasal
and prefrontals. These scales were given the rather
distinctive name of “boucliers”, which is actually
the French term for the carapace of crustaceans,
and were figured as two rather oblong scales lying
in the position of the frontonasal and prefrontals.
However, the actual specimen has a frontonasal and
two small, widely separated prefrontals; in other
words, a totally normal morphology. And strangely,
three lines later in the description, the existence of
prefrontals is acknowledged in using the prefrontal
to help describe the location of another scale.
The second significant error in the description
is the separation of the nasal and first infralabial
instead of their fusion. These two scales are not described, but the figure clearly shows the two scales
as being separate.
COMPARISON OF THE TWO SPECIMENS
OF SIAPHOS TRIDIGITUS
In the manus of MNHN 2003.3367, the metacarpals of digits 1 and 5 are obvious, demonstrating
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unequivocally that it is these digits that have been
lost. The two specimens of Siaphos tridigitus are
fairly similar to one another when the poor state
of preservation of the type is taken into account.
The two differ unequivocally in two regards. The
number of longitudinal scale rows at mid-body is
20 in the holotype and 18 in the new specimen.
Although skinks with very low mid-body scale
row counts tend to show little variation in this
variable, this difference is not significant. Similarly,
the number of paravertebral scales is 51 in the
holotype and 50 in the new specimen. Again, this
difference is trivial.
The poor state of preservation of the holotype
makes other possible differences between it and
the second specimen more equivocal. For example, the holotype appears to have the loreal fused
to the preocular, whereas the second specimen has
the two scales separate.
RELATIONSHIPS OF SIAPHOS TRIDIGITUS
Siaphos tridigitus is clearly a member of the Sphenomorphus group of lygosomine skinks (Greer 1979)
on the basis of supranasals absent and inner preanals
overlapping the outer preanals. The species has
several clearly derived character states within the
Sphenomorphus group and at least some of these
characters, if not all, might be expected to be shared
with in its closest relative. These characters are:
ZOOSYSTEMA • 2006 • 28 (3)
Siaphos tridigitus (Reptilia, Scincidae) from Southeast Asia
FIG. 3. — Head of the second specimen of Sphenomorphus tridigitus Bourret, 1939 (MNHN 2003.3367), with the taxonomically important
head scales labelled. See Abbreviations for the scale nomenclature, and: 1º, primary temporal; 2º, secondary temporal; 3º, tertiary
temporal. The small upper presubocular scale is not labelled. Scale bar: 1 mm.
ZOOSYSTEMA • 2006 • 28 (3)
789
Greer A. E. et al.
prefrontals small and widely separated (instead of
contacting); anterior supraciliary contacting frontal
(separated); nasal and first supralabial fused (distinct);
loreal single (two); supralabials six (seven); external
ear opening absent (present); infralabials contacted
by postmental one (two); presacral vertebrae 27
(26); digits of manus three, with phalanges 0.3.4.4.0
(2.3.4.5.3), and digits of pes with phalanges 2.3.4.4.3
(2.3.4.5.4).
Unfortunately, all but one of these characters are
common in the Sphenomorphus group, especially
among small species living in the litter. The exception is the fused nasal and first supranasal. This
character occurs elsewhere in the Sphenomorphus
group only in S. schultzei (Vogt, 1911) from New
Guinea. However, this latter species is part of the
species group Sphenomorphus maindroni (Sauvage,
1878), which has a unique character not seen
in Siaphos tridigitus (a pretemporal scale) and is
centred well to the east in New Guinea (Greer &
Shea 2004).
The genus Saiphos (as was the original spelling
[Gray 1831] and not the emended spelling Siaphos
[Gray 1839] used by Bourret [1939]) is now restricted
to a single species from southeastern Australia, the
semi-fossorial Saiphos aequalis (Gray, 1825). The two
species share a number of derived characters, but the
wide geographical separation between the two species would suggest that the similarity is convergent.
Furthermore, most of the semi-fossorial and fully
fossorial species of southeast Asia such as Isopachys
Lönnberg, 1916, Larutia Böhme, 1981, Leptoseps
Greer, 1997 and Parvoscincus Ferner, Brown &
Greer, 1997 also share many of the species’ derived
characters and on geographical grounds are more
likely to be related to it.
There are also a few small species in southeast
Asia (Table 1) that are not as modified as some of
the more fossorial species in the area and also share
several of the derived characters of Siaphos tridigitus.
These species are currently placed in the catch-all
genus Sphenomorphus Fitzinger, 1843, and we rec-
ommend that Siaphos tridigitus be relegated to this
group pending its taxonomic subdivision.
Acknowledgements
We are grateful to Ivan Ineich (MNHN) for his
assistance in the preparation of this paper.
REFERENCES
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Submitted on 28 May 2004;
accepted on 3 June 2005.
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